DESCRIPTION

Reads list of objects from the standard input, and writes a packed
archive with specified base-name, or to the standard output.

A packed archive is an efficient way to transfer a set of objects
between two repositories as well as an access efficient archival
format. In a packed archive, an object is either stored as a
compressed whole or as a difference from some other object.
The latter is often called a delta.

The packed archive format (.pack) is designed to be self-contained
so that it can be unpacked without any further information. Therefore,
each object that a delta depends upon must be present within the pack.

A pack index file (.idx) is generated for fast, random access to the
objects in the pack. Placing both the index file (.idx) and the packed
archive (.pack) in the pack/ subdirectory of $GIT_OBJECT_DIRECTORY (or
any of the directories on $GIT_ALTERNATE_OBJECT_DIRECTORIES)
enables Git to read from the pack archive.

The git unpack-objects command can read the packed archive and
expand the objects contained in the pack into "one-file
one-object" format; this is typically done by the smart-pull
commands when a pack is created on-the-fly for efficient network
transport by their peers.

OPTIONS

base-name

Write into a pair of files (.pack and .idx), using
<base-name> to determine the name of the created file.
When this option is used, the two files are written in
<base-name>-<SHA-1>.{pack,idx} files. <SHA-1> is a hash
based on the pack content and is written to the standard
output of the command.

--stdout

Write the pack contents (what would have been written to
.pack file) out to the standard output.

--revs

Read the revision arguments from the standard input, instead of
individual object names. The revision arguments are processed
the same way as git rev-list with the --objects flag
uses its commit arguments to build the list of objects it
outputs. The objects on the resulting list are packed.
Besides revisions, --not or --shallow <SHA-1> lines are
also accepted.

--unpacked

This implies --revs. When processing the list of
revision arguments read from the standard input, limit
the objects packed to those that are not already packed.

--all

This implies --revs. In addition to the list of
revision arguments read from the standard input, pretend
as if all refs under refs/ are specified to be
included.

--include-tag

Include unasked-for annotated tags if the object they
reference was included in the resulting packfile. This
can be useful to send new tags to native Git clients.

--window=<n>

--depth=<n>

These two options affect how the objects contained in
the pack are stored using delta compression. The
objects are first internally sorted by type, size and
optionally names and compared against the other objects
within --window to see if using delta compression saves
space. --depth limits the maximum delta depth; making
it too deep affects the performance on the unpacker
side, because delta data needs to be applied that many
times to get to the necessary object.
The default value for --window is 10 and --depth is 50.

--window-memory=<n>

This option provides an additional limit on top of --window;
the window size will dynamically scale down so as to not take
up more than <n> bytes in memory. This is useful in
repositories with a mix of large and small objects to not run
out of memory with a large window, but still be able to take
advantage of the large window for the smaller objects. The
size can be suffixed with "k", "m", or "g".
--window-memory=0 makes memory usage unlimited, which is the
default.

--max-pack-size=<n>

Maximum size of each output pack file. The size can be suffixed with
"k", "m", or "g". The minimum size allowed is limited to 1 MiB.
If specified, multiple packfiles may be created.
The default is unlimited, unless the config variable
pack.packSizeLimit is set.

--honor-pack-keep

This flag causes an object already in a local pack that
has a .keep file to be ignored, even if it would have
otherwise been packed.

--incremental

This flag causes an object already in a pack to be ignored
even if it would have otherwise been packed.

--local

This flag causes an object that is borrowed from an alternate
object store to be ignored even if it would have otherwise been
packed.

--non-empty

Only create a packed archive if it would contain at
least one object.

--progress

Progress status is reported on the standard error stream
by default when it is attached to a terminal, unless -q
is specified. This flag forces progress status even if
the standard error stream is not directed to a terminal.

--all-progress

When --stdout is specified then progress report is
displayed during the object count and compression phases
but inhibited during the write-out phase. The reason is
that in some cases the output stream is directly linked
to another command which may wish to display progress
status of its own as it processes incoming pack data.
This flag is like --progress except that it forces progress
report for the write-out phase as well even if --stdout is
used.

--all-progress-implied

This is used to imply --all-progress whenever progress display
is activated. Unlike --all-progress this flag doesn’t actually
force any progress display by itself.

-q

This flag makes the command not to report its progress
on the standard error stream.

--no-reuse-delta

When creating a packed archive in a repository that
has existing packs, the command reuses existing deltas.
This sometimes results in a slightly suboptimal pack.
This flag tells the command not to reuse existing deltas
but compute them from scratch.

--no-reuse-object

This flag tells the command not to reuse existing object data at all,
including non deltified object, forcing recompression of everything.
This implies --no-reuse-delta. Useful only in the obscure case where
wholesale enforcement of a different compression level on the
packed data is desired.

--compression=<n>

Specifies compression level for newly-compressed data in the
generated pack. If not specified, pack compression level is
determined first by pack.compression, then by core.compression,
and defaults to -1, the zlib default, if neither is set.
Add --no-reuse-object if you want to force a uniform compression
level on all data no matter the source.

--thin

Create a "thin" pack by omitting the common objects between a
sender and a receiver in order to reduce network transfer. This
option only makes sense in conjunction with --stdout.

Note: A thin pack violates the packed archive format by omitting
required objects and is thus unusable by Git without making it
self-contained. Use git index-pack --fix-thin
(see git-index-pack[1]) to restore the self-contained property.

--shallow

Optimize a pack that will be provided to a client with a shallow
repository. This option, combined with --thin, can result in a
smaller pack at the cost of speed.

--delta-base-offset

A packed archive can express the base object of a delta as
either a 20-byte object name or as an offset in the
stream, but ancient versions of Git don’t understand the
latter. By default, git pack-objects only uses the
former format for better compatibility. This option
allows the command to use the latter format for
compactness. Depending on the average delta chain
length, this option typically shrinks the resulting
packfile by 3-5 per-cent.

Note: Porcelain commands such as git gc (see git-gc[1]),
git repack (see git-repack[1]) pass this option by default
in modern Git when they put objects in your repository into pack files.
So does git bundle (see git-bundle[1]) when it creates a bundle.

--threads=<n>

Specifies the number of threads to spawn when searching for best
delta matches. This requires that pack-objects be compiled with
pthreads otherwise this option is ignored with a warning.
This is meant to reduce packing time on multiprocessor machines.
The required amount of memory for the delta search window is
however multiplied by the number of threads.
Specifying 0 will cause Git to auto-detect the number of CPU’s
and set the number of threads accordingly.

--index-version=<version>[,<offset>]

This is intended to be used by the test suite only. It allows
to force the version for the generated pack index, and to force
64-bit index entries on objects located above the given offset.

--keep-true-parents

With this option, parents that are hidden by grafts are packed
nevertheless.